1. Field of the Invention
The present invention relates to a method of manufacturing a developer container to be used in an image forming apparatus such as a copying machine, a printer, and a facsimile machine of an electrophotographic printing method or an electrostatic recording process, and to a developer container, a developing apparatus, a process cartridge, and an image forming apparatus.
2. Description of the Related Art
Electrophotographic image forming apparatus, for example, are hitherto provided with a developing apparatus configured to form a developer image by supplying a developer to an electrostatic latent image formed on an electrophotographic photosensitive member (photosensitive member) as an image bearing member. In recent years, developing cartridges or process cartridges are widely used which include the developing apparatus alone or along with other process means and which are detachably mountable to the main body of the image forming apparatus.
A cartridge method in which a developing cartridge or a process cartridge (The developing cartridge or the process cartridge may hereinafter simply be referred to as “cartridge”.) is detachably mountable to the main body of an image forming apparatus facilitates the supplying of the developer and other types of maintenance work.
For the cartridge method, in general, an operator such as a user or a service person replaces the cartridge or supplies the developer at the time the developer in a developer container of the developing apparatus is used up, thereby enabling the image forming apparatus to form images again. It is therefore common for an image forming apparatus of the cartridge method to have detecting means for detecting the amount (remaining amount) of the developer in order to detect the consumption of the developer and inform the user or others of when to replace the cartridge.
A type of the detecting means is one that uses a capacitance detection method in which, as disclosed in Japanese Patent Application Laid-Open No. 2001-117346, the developer amount is detected by providing a pair of an input-side electrode and an output-side electrode to measure the capacitance between the electrodes. The electrodes are in general antenna members which are made of metal and shaped into a plate (SUS sheet metal or the like).
Japanese Patent Application Laid-Open No. 2003-248371 discloses another example in which a developer carrying member in a developing apparatus that applies an AC voltage to the developer carrying member serves as the input-side electrode and a capacitance detecting member serving as the output-side electrode is arranged in the developing apparatus so as to face the developer carrying member. This capacitance detecting member also is in general an antenna member which is made of metal and shaped into a plate (SUS sheet metal or the like).
The capacitance between the electrodes (between the antenna members, or between the developer carrying member and the antenna member) in the capacitance detection method varies depending on the amount of the developer which is constituted of an insulating toner and others. Specifically, the capacitance between the electrodes is large when the space between the electrodes is filled with the developer, and decreases as the developer dwindles and air takes up the space between the electrodes at an increasing ratio. Accordingly, the developer amount can be detected by obtaining the relation of the developer amount to the capacitance between the electrodes in advance and measuring the capacitance.
However, using the electrode plates described above, such as SUS sheet metal, for the antenna members tends to increase the cost of parts relatively. Consequently, increasing the antenna members in size or number in order to, for example, improve the precision of developer amount detection or accomplish successive detection of the remaining developer amount from an earlier stage at the start of use is likely to increase the cost of the developer container and other components.
Japanese Patent Application Laid-Open No. 2002-40906 discloses, as a method of fixing the antenna members, a method that uses a double-sided adhesive tape to stick the antenna members to a frame that forms a developer container of a developing apparatus. Japanese Patent Application Laid-Open No. 2002-40906 also discloses that, as an alternative, a conductive paint layer or vapor deposition layer may be formed directly on the frame by performing printing or evaporation directly on the frame, or a conductive portion may be formed by the two-color molding of conductive resin, but does not disclose a detailed description of the alternative.
Japanese Patent Application Laid-Open No. H08-15975 discloses a method of forming an electrode layer by applying a coating solution in which an appropriate amount of fine carbon black particles is dispersed in a blend solution of a urethane resin and a vinyl chloride resin to a sheet base and thermally curing the applied coat.
However, the methods described above which involve sticking the antenna members to the frame with double-sided adhesive tape or forming the antenna members on the frame by evaporation or printing tend to complicate the manufacturing steps for reasons including the need for a step of processing the frame after the forming of the frame.